How to see HDD temperatures under Ubuntu server

There is a small apllication called hddtemp, which shows you the temperature of your HDD by reading data from S.M.A.R.T. on drives that support this feature. Most modern x86 computer hard disk comes with S.M.A.R.T (Self-Monitoring, Analysis, and Reporting Technology). It is a monitoring system for computer hard disks to detect and report on various indicators of reliability, in the hope of anticipating failures.